Paul Bagot

Profile Information
Name
Prof. Paul Bagot
Institution
University of Oxford
Position
Associate Professor of Materials/AP Group Leader
h-Index
49
ORCID
0000-0002-9102-6083
Biography
Assoc. Prof. Paul Bagot is head of the Oxford Atom Probe group. He oversees and supports research using APT and other complementary, high-resolution techniques to understand the relationship between atomic-scale structure/composition and materials performance. His research background covers understanding Pt-group metal interactions with gaseous reactants for pollution control/chemicals production and oxidation of engineering alloys for developing more efficient, cleaner gas-turbine aerospace engines. He leads several research projects investigating structural materials for fission and fusion power, and lightweight, energy-saving aluminium alloys for automotive applications. He has a strong interest in the development of novel fields for APT, including fuel cells, solar power structures and battery devices. He actively collaborates with many UK-based and international institutions, including as a ‘Visiting Researcher for Correlative Atom Probe Tomography Development’ at the University of Glasgow.
Publications:
"Atom probe characterisation of segregation driven Cu and Mn–Ni–Si co-precipitation in neutron irradiated T91 tempered-martensitic steel" Paul Bagot, Maria A Auger, Nathan Almirall, Peter Hosemann, G. Robert Odette, Michael Moody, DAvid ARmstrong, Materialia Vol. 14 2020 Link
The T91 grade and similar 9Cr tempered-martensitic steels (also known as ferritic-martensitic) are leading candidate structural alloys for fast fission nuclear and fusion power reactors. At low temperatures (300–400 °C) neutron irradiation hardens and embrittles these steels, therefore it is important to investigate the origin of this mode of life limiting property degradation. T91 steel specimens were separately neutron irradiated to 2.14 dpa at 327 °C and 8.82 dpa at 377 °C in the Idaho National Laboratory Advanced Test Reactor. Atom probe tomography was used to investigate the segregation driven formation of Mn–Ni–Si-rich (MNSPs) and Cu-rich (CRP) co-precipitates. The precipitates increase in size and, slightly, in volume fraction at the higher irradiation temperature and dose, while their corresponding compositions were very similar, falling near the Si(Mn,Ni) phase field in the Mn–Ni–Si projection of the Fe-based quaternary phase diagram. While the structure of the precipitates has not been characterised, this composition range is distinctly different than that of the typically cited G-phase. The precipitates are composed of CRP with MNSP appendages. Such features are often observed in neutron irradiated reactor pressure vessel (RPV) steels. However, the Si, Ni, Mn, P and Cu solutes concentrations are lower in the T91 than in typical RPV steels. Thus, in T91 precipitation primarily takes place in solute segregated regions of line and loop dislocations. These results are consistent with the model for radiation induced segregation driven precipitation of MNSPs proposed by Ke et al. Cr-rich alpha prime (α’) phase formation was not observed.